Larger wind turbines can generate more electricity, but is that extra energy greener?

The answer is yes, the bigger the turbine the greener the energy, according to Marloes Caduff and her colleagues at the Institute for Environmental Engineering in Zurich who published a study in the journal Environmental Science and Technology. But the answer is complex.

It may seem odd to question the eco-friendliness of a renewable energy source. But Caduff and her team determined that if the production, transport, and retirement of bigger turbines is too environmentally-taxing, the trend towards larger ones won’t be good for the environment.

So the researchers devised a method to calculate the technology’s “global warming potential.”

The bigger the wind turbine, the greener the energy.

To do this, the team borrowed the economic concept of progress rates. In an email interview, Caduff noted that, “if the progress rate is 100 percent, no learning takes place, hence no cost reduction is observed. So the lower the progress rate, the better.” The same applies for global warming potential: the smaller the number, the better.

To calculate global warming potential, the researchers looked at resource extraction, production of the turbines, disposal, as well as the learning curve for businesses to adopt the new manufacturing process.

By looking at “the impact per produced kilowatt hour (kWh) versus the total cumulative installation and production of wind turbines in Europe,” Caduff said, they found the environmental impact was reduced as more turbines were installed. The calculated environmental progress rate was 86 percent, resulting in a reduced global warming potential of 14 percent.

In other words: using more, big turbines is 14 percent better for the environment.

Because this result was calculated using data from Europe, adaptations would need to be made to determine its validity for other places. “Important changes would be the used electricity mix, wind speeds and wind shear, transport distances, raw material production and disposal,” says Caduff.

Still, the results can help wind turbine producers or investors of wind farms “determine the global warming potential impacts of turbines, ranging between 12.5 and 90 meters in diameter, without having to perform an entire life-cycle analysis study,” according to Caduff. This saves both time and money, which will help spur on the trend towards larger turbines.

And if bigger turbines equal a cleaner environment, this is a trend worth following.